Processing device, processing method, and storage medium

ABSTRACT

Provided is a processing device capable of, on the basis of data prepared by a recorder that only has recording function, acquiring information related to a time when the data was prepared. The processing device includes an acquisition unit for acquiring the recorded audio data, and an identification unit for detecting a sound signal that is included in the audio data and transmitted from an information transmission device and allows the time at which the signal was recorded to be identified, and identifying the time when other signals included in the audio data were recorded on the basis of the sound signal.

TECHNICAL FIELD

The present disclosure relates to a technique for analyzing a sound, andsynchronizing time of a plurality of data.

BACKGROUND ART

A technique for analyzing sound such as environmental sound, voice andthe like, and detecting an event occurred on the basis ofcharacteristics of the sound is known. The sound representing the eventoccurred is sometimes called an audio event, an audio incident or thelike. A technique for preliminarily defining an audio event and, fromamong collected sound data, detecting and identifying the audio eventsignifying the same characteristics as a defined audio event is calledaudio event detection.

For example, a technique for arranging a plurality of audio sensors (inother words, microphones) in a distributed manner, and detecting anaudio event in the area in which the sensors are arranged is known. As arelated technique, NPL 1 discloses a technique for preciselysynchronizing using the same radio broadcast signals in order tosynchronize the sampling of the plurality of microphones arranged in awide area.

In addition, PTL 1 is a literature disclosing a synchronization ofinternal time of a plurality of recorders. When synchronizing, therecorders are connected to one another, and the time is set using adedicated circuit.

PTL 2 discloses a technique for including information signifying astarting point of the watermark information (i.e., a synchronizingpoint) in sound data.

PTL 3 discloses a technique, which is not related to an analysis ofsound, for adjusting delay difference of the two transmission linesusing a frame identification signal. PTL 4 discloses a technique forsetting the time through receiving an electric wave including timeinformation.

CITATION LIST Patent Literature

-   [PTL 1] Unexamined Japanese Patent Application Publication No.    2000-251399-   [PTL 2] Unexamined Japanese Patent Application Publication No.    2013-101284-   [PTL 3] Unexamined Japanese Patent Application Publication No.    2003-234726-   [PTL 4] Unexamined Japanese Patent Application Publication No.    2000-162346

Non Patent Literature

-   [NPL 1] “Sampling Synchronization Using Radio Broadcast Signals for    Distributed Microphone Arrays”, HOSHUYAMA Osamu, Technical report of    IEICE (The Institute of Electronics, Information and Communication    Engineers), IEICE, May 2015, vol. 114, No. 474, pp. 313-316.

SUMMARY OF INVENTION Technical Problem

When an audio event is detected from audio data recorded by a recorder(hereinafter referred to as audio data) as the techniques disclosed inPTL 1 and NPL 1, the occurrence time of the audio event can beidentified if the time information is related to the audio data.

However, equipping the recorder with a function for relating accuratetime information with the audio data takes a certain level of cost. Forexample, the recorder of PTL 1 needs to be equipped with a dedicatedcircuit for synchronization. With the technique disclosed in NPL 1,installation of an antenna for receiving radio signal is necessary, andthere is a limitation in the equipment configuration, and, largecomputer resource is necessary.

When a function for relating the time information with the audio data isnot provided, and especially, when the recorder does not incorporate aclock or does not have a function to calibrate the clock, it isdifficult to correctly identify the occurrence time of the audio event.In addition, in such a case, measuring ambient sound using a pluralityof recorders and relating audio events included in the audio datacollected by each recorder to one another is difficult. In other words,recorders that do not have a configuration dedicated for synchronizationand time adjustment do not contribute to identification of the sameaudio event recorded to a plurality of recorders.

One of the objectives of the present invention is to provide aprocessing device that can acquire, on the basis of data generated by arecorder having only a recording function, information related to thetime at which the data is generated.

Solution to Problem

A processing device according to one aspect of the present inventionincludes an acquisition means for acquiring recorded audio data, and anidentification means for detecting a signal of a sound included in theaudio data, the signal being emitted from an information emission deviceand enabling identification of time at which the signal is recorded, andon the basis of the signal, identifying time at which another signalincluded in the audio data is recorded.

A processing method according to one aspect of the present inventionacquires recorded audio data, detects a signal, the signal beingincluded in the audio data and enabling identification of time at whichthe signal is recorded, and on the basis of the signal, identifies timeat which another signal included in the audio data is recorded.

A program according to one aspect of the present invention causes acomputer to execute an acquiring process for acquiring recorded audiodata, and an identification process for detecting a signal, the signalbeing included in the audio data and enabling identification of time atwhich the signal is recorded, and an identifying process foridentifying, on the basis of the signal, time at which another signalincluded in the audio data is recorded.

Advantageous Effects of Invention

According to the present invention, on the basis of data generated by arecorder having only a recording function, information related to timethe data are generated can be acquired.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a configuration of a signalprocessing system according to the first example embodiment of thepresent invention.

FIG. 2 is a flow chart illustrating a flow of an operation of the signalprocessing system according to the first example embodiment.

FIG. 3 is a block diagram illustrating a configuration of a signalprocessing system according to a second example embodiment of thepresent invention.

FIG. 4 is a diagram illustrating an example of audio data generated byeach of the two recorders.

FIG. 5 is a diagram illustrating a concept of adjusting time axes.

FIG. 6 is a flow chart illustrating a flow of an operation of each unitof the signal processing system according to the second exampleembodiment.

FIG. 7 is a diagram illustrating a concept of adjusting time axes on thebasis of a discrepancy between two clocks.

FIG. 8 is a block diagram illustrating a configuration of a signalprocessing system according to a third example embodiment of the presentinvention.

FIG. 9 is a diagram illustrating an example of audio data generated by arecorder according to the third example embodiment.

FIG. 10 is a block diagram illustrating a configuration of a signalprocessing system according to a fourth example embodiment of thepresent invention.

FIG. 11 is a block diagram illustrating a configuration of a processingdevice 20 according to a fifth example embodiment of the presentinvention.

FIG. 12 is a flow chart illustrating a flow of an operation of theprocessing device 20 according to the fifth example embodiment.

FIG. 13 is a block diagram illustrating a configuration of a signalprocessing system according to the fifth example embodiment.

FIG. 14 is a block diagram illustrating an example of a hardwareachieving each unit of each example embodiment of the present invention.

EXAMPLE EMBODIMENT

Hereinafter, example embodiments of the present invention will bedescribed with reference to figures.

First Example Embodiment

A first example embodiment of the present invention is described.

<Configuration>

FIG. 1 is a block diagram illustrating an overall configuration of aninformation emission device and a signal processing system 1 to whichthe information emission device and the processing device according tothe first example embodiment are employed.

The signal processing system 1 includes an information emission device11, a processing device 21, and a recorder 30.

===Recorder 30===

The recorder 30 is installed at a place where a user wants to collectaudio events, and collects ambient sound. The recorder 30 records theaudio signal input to an incorporated microphone in a recordable area astime series data of a sound, for example. The recorder 30 may be amachine that records a sound in analog format such as an analog taperecorder. Hereinafter, processing of collecting of the ambient sound andgenerating data of the collected ambient sound performed by the recorder30 is referred to as “recording”. Hereinafter, the data generated by therecorder 30 by recording is referred to as “audio data”.

The recorder 30 may not necessarily be synchronized with some standardtime system. However, the recorder 30 records a sound in time order in apredetermined constant recording speed. For example, when the recordingmethod of the recorder 30 is digital recording, the recorder 30 acquiresand records an amplitude of the sound wave at a predetermined timeinterval. When the recording method of the recorder 30 is analogrecording, the recorder 30 fixes (records) a sound on a tape that movesin a predetermined speed. As a result, an audio signal in the generatedaudio data and the elapsed time from the time at which the recordingstarted can be related to each other. In other words, the time at whichthe signal in the audio data is recorded can be relatively identifiedusing the starting time of the audio data as a point of reference, forexample.

The recorder 30 may have an internal storage area, or may becommunicatively connected to a storage device. When the recorder 30 iscommunicatively connected to a storage device, the recorder 30 mayrecord audio data on the storage device. The recorder 30 may send audiodata to the processing device 21.

===Information Emission Device 11===

The information emission device 11 includes a clock 110, a control unit111, a timing storage unit 112, a time information generation unit 113,a time code storage unit 114, and an emission unit 115.

The clock 110 provides time to the control unit 111. The time providedby the clock 110 is, for example, the standard time of the country inwhich the signal processing system 1 is implemented. The clock 110 maysynchronize at any time with an accurate external time source using GPS(Global Positioning System) or the like in order to acquire the accuratestandard time. The time provided by the clock 110 may be set by aperson.

Precision of the clock 110 may not be rigorous. The time provided by theclock 110 may be the time proper enough for the system to achieve theobjective. For example, it may be permissive if the maximum value of theerror of clocking by the clock 110 may be 0.5 second per week.

The clock 110 outputs the information signifying the time that is beingclocked, using a crystal oscillator for example, at fixed time periodsto the control unit 111.

The timing storage unit 112 stores information that specifies the timingthat the emission unit 115 emits time information. The time informationwill be described later. The information specifying the timing ispreliminarily set by the user for example. For example, 0:00, 7:00,12:30, 18:00, and 21:00 are set as the timing for emitting the timeinformation, and the time that is set is stored in the timing storageunit 112.

The set timing may be stored in a format such as “0 minutes 00 secondsevery hour”. In addition, when the recording of the sound is continuedover a plurality of days, different times may be set for each day.

The control unit 111 watches the time provided by the clock 110. Thecontrol unit 111 calls the time information generation unit 113 when thetime provided by the clock 110 matches the time signified by the timingstorage unit 112. The control unit 111 may send, to the time informationgeneration unit 113, information signifying the time provided by theclock 110 that matches the time signified by the timing storage unit112.

The time information generation unit 113 generates time information.Time information is the information signifying the time, and isinformation that may be signified by a sound.

Time information includes, for example, information signifying that theinformation itself is time information, and information signifying time.Hereinafter, the information signifying that the information is the timeinformation is referred to as “indication information”. The informationsignifying the time is referred to as “time code”. The indicationinformation and the time code may not be separate, and may berepresented by one signal.

The indication information may include a characteristic that enablesidentification unit 212 of the processing device 21, which will bedescribed below, to detect that the time information is signified. Forexample, the indication information may include frequency, volume, andother characteristics that are not usually detected from the ambientsound recorded by the recorder 30.

The time code is, for example, information of the time that is convertedto information having the form of a sound. The time informationgeneration unit 113 may convert the time information received from thecontrol unit 111, or use a preliminarily prepared time code. Forexample, the time code storage unit 114 may store the time code, and thetime information generation unit 113 may receive the time code.

There are various known methods for converting the time information intoaudio. For example, the time code may be generated by the method oftranslating information into audio, used by a modem and an acousticcoupler. The time code may be time information or the like that isembedded in the audio using an audio watermarking technique. The timecode may be represented by a time series pattern of audio such as Morsecode, or may be represented by the number of times of appearance of theaudio as seen in the cuckoo clock. In addition, the time code may notrepresent the time itself. For example, the time information may beencoded using a rule such as 0.5 seconds of 2000 Hz audio waverepresents seven o'clock. Therefore, the time information generationunit 113 may indirectly express the time using the signal preliminarilydefined for the time information generation unit 113 and the processingdevice 21.

The emission unit 115 is a speaker, for example. The emission unit 115converts the time information generated by the time informationgeneration unit 113 to sound which is the vibration of the air, andemits the sound.

The emission unit 115 is arranged at a position where the sound emittedby the emission unit 115 is acquired by the recorder 30.

With the configuration described above, the sound by which the time canbe identified is recorded on the recorder 30. In other words, the audiodata including the time information are generated by the recorder 30.

When there is a time lag that cannot be ignored between the time atwhich the control unit 111 calls the time information generation unit113 and the time at which the time information is emitted by theemission unit 115, a measure to adjust the time lag may be taken. Forexample, the control unit 111 may call the time information generationunit 113 when the time difference between the time shown by the clock110 and the time shown by the timing storage unit 112 becomes less thana predetermined value. Alternatively, for example, the time informationgeneration unit 113 may add a time in which the time lag is taken intoconsideration to the received time, and convert a resulting time to atime code.

===Processing Device 21===

The control structure of the processing device 21 will be described.

The processing device 21 includes an acquisition unit 211, anidentification unit 212, a detection unit 214 and an output unit 215.

The acquisition unit 211 acquires audio data from the recorder 30. Forexample, when the audio data are recorded in an internal storage mediumof the recorder 30, a person attaches the storage medium to theacquisition unit 211, and the acquisition unit 211 reads the audio data.In such a case, the acquisition unit 211 is, for example, a drive thatcan read the information recorded on the storage medium. The acquisitionunit 211 may receive the audio data by communicating with the recorder30 or a storage medium on which the audio data are recorded. In such acase, the acquisition unit 211 is a communication interface for example.The audio data may not necessarily be acquired in real time.

The acquisition unit 211 transmits the acquired data to theidentification unit 212.

The identification unit 212 identifies the time at which the audio dataare recorded on the basis of the time information included in the audiodata. Specifically, the identification unit 212 performs the followingprocess, for example.

Firstly, the identification unit 212 detects the time informationincluded in the audio data. The identification unit 212 may firstlydetect the indication information from the audio data, and then detectthe time code on the basis of the indication information.

The identification unit 212 detects the indication information bysearching for the indication information included in the audio data.When the frequency in which the characteristic of the indicationinformation appears is known, a frequency component at that frequency ofthe audio data may be searched. The identification unit 212 identifiesthe time code through detecting the indication information.

The identification unit 212 decodes the time code. A decoding method ofthe time code may be preliminarily determined in such a way as not toconflict with the time information generation unit 113 (or the time codestorage unit 114) which generates the time code. The identification unit212 acquires the time information signified by the time code by decodingthe time code. Since the time signified by the time code is the time atwhich the time information including the time code is emitted, theidentification unit 212 is able to identify the time at which the timeinformation is emitted by decoding the time code. For example, when thetime code is set on the information emission device 11 side so as tosignify the time at which the indication information started to ring,the identification unit 212 identifies that starting point of thedetected indication information in the audio data is the time signifiedby the time code.

The identification unit 212 is able to identify the time at any point inthe audio data because the time at a point in the audio data can beidentified. For example, the time code signifying the time t₀ isdetected at a point 30 seconds after the start of the sound indicated bythe audio data, the time at which the generation of the audio datastarted is understood to be 30 seconds before the t₀. As describedabove, the identification unit 212 is able to relate the audio data andthe time. The time in the present example embodiment is the time of theclock 110 of the information emission device 11. When the clock 110 issynchronized with the standard time of a country, the time identified bythe identification unit 212 is the standard time of the country.

The detection unit 214 detects an audio event included in the audiodata. The audio event is the sound that has a prescribed characteristic.For example, the audio event is the sound signifying the event(incident) preliminarily specified to the detection unit 214 that showsthe event (incident) that the user wants to detect.

Note that Literature 1 and Literature 2 are the examples of literaturerelated to detection and analysis of an audio event.

-   Literature 1: “Toward detection and discrimination of all    sounds—present and future of audio event detection—”, OHISHI    Yasunori, The Acoustical Society of Japan Proceedings, Acoustical    Society of Japan, 2014, pp. 1521-1524.-   Literature 2: “Sound and Audio Analysis Technique and Application to    Public Solution”, KOSHINAKA Takafumi, et al., NEC(Nippon Electric    Company) Technical Journal, NEC corporation, November 2014, vol. 67,    No. 1, pp. 86-89.

An audio event is a sound that satisfies a condition preliminarilydefined by a user, for example. For example, the detection unit 214stores a feature of the indicated audio event, and the predeterminedstandard related to the similarity to the feature. Then, the detectionunit 214 extracts, as the audio event, the sound having a feature inwhich the similarity to the feature of the indicated audio eventconforms to the predetermined standard.

The preliminarily defined condition may not be the condition related toa specific event. For example, the sound whose volume exceeds aprescribed value may be specified as the audio event that the user wantsto detect.

A plurality of types of audio events may exist. For example, the soundof hitting a metal plate, the sound of hitting a glass plate, and ascream may be set as three types of audio events. Each of the audioevents may be classified into one of a plurality of classes. Forexample, since the sound of hitting a metal plate resembles the sound ofhitting a glass plate, these two types of sounds may be classified to asame class. When the audio event has been classified, informationindicating relation between the audio event and the class may be storedby the detection unit 214 as the information signifying theclassification of the audio event, for example.

The detection unit 214 detects the audio event and the time at which theaudio event occurred. Alternatively, the identification unit 212 mayidentify the time at which the audio event detected by the detectionunit 214 occurred, and may relate the identified time to the detectedaudio event.

The output unit 215 outputs information in which the detected audioevent and the time at which the audio event occurred are related.

For example, the output unit 215 may display a list signifying the audioevents and the time at which the audio events occurred on a screen. Whena detection of one audio event is demanded, the output unit 215 maydisplay only the time at which the audio event occurred on the screen.

<Operation>

A flow of an operation of the signal processing system 1 according tothe first example embodiment will be described with reference to theflow chart of FIG. 2.

Firstly, the recorder 30 starts recording the ambient sound (step S41).For example, a person may start the recorder.

Then, in the information emission device 11, when the time of the clock110 becomes the time stored by the timing storage unit 112, the callingby the control unit 111 causes the time information generation unit 113to generate time information (step S42).

As a timing for emitting time information, time that is estimated tohave low possibility of occurrence of an audio event to be detected, ortime at which the audio event to be detected is estimated not to occurmay be set. For example, a user may estimate the time at which the audioevent the user wants to detect is less likely to occur or does notoccur, and may set the estimated time as the timing for emitting thetime information. Alternatively, the information emission device 11 mayestimate, on the basis of data of the past audio events and the like,the time at which the audio event is less likely to occur, and may setthe estimated time as the timing for emitting the time information. Withthe above-described setting, detection of the time information by theidentification unit 212 becomes easy, and detection of the audio eventto be detected becomes less likely to be disturbed.

In addition, when there is a timing at which the user determines that anaudio event is not necessary to be detected, the user may set the timingas the timing for emitting the time information.

When there is a frequency band that is irrelevant to the target audioevent or the environmental sound (in other words, when other signals donot interfere or disturb the detection of time information in thefrequency band), the time information generation unit 113 may set thetime information in such a way that the frequency of the timeinformation ranges within the frequency band. As a result of configuringas described above, the time information and the environmental sound(and consequently the audio event) are not confused, and the accuracy ofthe detection of the time information by the identification unit 212 andthe detection of the audio event by the detection unit 214 can beincreased.

When the time information is generated, the emission unit 115 emits thetime information (step S43). As a result, the recorder 30 records notonly the ambient sound, but also the time information emitted by theemission unit 115 (on the same channel).

When the time to finish the collection of the audio data has come, therecorder 30 stops recording (step S44). A person may stop the operationof the recorder 30, or the recorder 30 may have a structure to finishrecording when a predetermined period of time passes after the recordingstarted. In the present example embodiment, the described is performingthe process of the following steps after finishing the recording,however, finishing of the recording may not necessarily be required forthe process of the following steps in some example embodiments.

Then, in the processing device 21, the acquisition unit 211 acquires theaudio data acquired by the recorder 30 (step S45). The identificationunit 212 identifies the time at which the audio data are recorded on thebasis of the time information included in the audio data (step S46).

Meanwhile, the detection unit 214 detects an audio event included in theaudio data (step S47). The identification unit 212 relates the time tothe detected audio event (step S48).

Finally, the output unit 215 outputs the information in which the audioevent and the time are related (step S49).

<Effect>

With the signal processing system 1 according to the first exampleembodiment, the time at which the audio data are generated, and the timeat which a certain signal in the audio data (especially, the audioevent) is generated can be identified. The reason is that, the timeinformation signifying the time emitted by the information emissiondevice 11 is included in the audio data, and the processing device 21detects the time information. In this system, since the informationsignifying the time is not an electric signal but a sound, the recorder30 only needs to have a recording function. In other words, the recorder30 does not need to include a special channel or a circuit, and may bean inexpensive recorder on the market.

As described above, according to the present example embodiment, on thebasis of data generated by the recorder having only the recordingfunction, the time at which the data are generated and the occurrencetime of any signal in the data can be identified.

(Modification)

In the above description, the clock 110 is set to match the standardtime or the like. However, the clock 110 may not be set to match thestandard time or the like. The clock 110 may have internal time. In sucha case, the detected audio event can be related to the internal time ofthe information emission device 11. For example, when time informationsignifying “seven o'clock” is included in the audio data, theidentification unit 212 understands that the time information is emittedat seven o'clock in the internal time of the information emission device11 (i.e., at the time at which the clock 110 recognizes as seveno'clock).

In such a case, the processing device 21 may be configured to be able toacquire information of time provided by the clock 110. For example, theprocessing device 21 may be communicatively connected to the clock 110,or may be configured to be able to detect the sound emitted from theemission unit 115 directly. By comparing time provided by the clock 110and time based on another time system other than the time system ofclock 110 (for example, the standard time of the country), theprocessing device 21 is able to identify the difference between the timesystem of clock 110 and the another time system. Consequently, theidentification unit 212 is able to relate the detected audio event andthe time based on the another time system.

(Modification)

The method in which the emission unit 115 causes the recorder 30 torecord the time information may not necessarily be a method involving anemission of a sound. The emission unit 115 may generate anelectromagnetic noise that can reach an internal microphone amplifier ora power source of the recorder 30. The emission unit 115 may physicallystrike or give vibration to the recorder.

In other words, the information emitted by the emission unit 115 mayhave any form of information that is reflected onto the audio data ofthe recorder 30.

Second Example Embodiment

The signal processing system 2 according to a second example embodimentwill be described.

<Configuration>

FIG. 3 is a block diagram illustrating a configuration of the signalprocessing system 2. The signal processing system 2 includes a pluralityof information emission devices 11, a plurality of recorders 30, and aprocessing device 22.

Each of the recorders 30 may be same as the recorder 30 in the firstexample embodiment. The three recorders 30 in FIG. 3 are given referencesigns 30A, 30B and 30C, respectively. However, the number of therecorders 30 is not limited to three. Hereinafter, when the recordersare to be distinguished, reference signs with alphabets such as 30A, 30Band 30C are given. When the recorders are generally referred or notidentified, reference number “30” is given.

In the present example embodiment, each of the plurality of recorders 30are arranged at different places. The area the recorder 30A is arrangedis an observation site 8A, the area the recorder 30B is arranged is anobservation site 8B, the area the recorder 30C is arranged is anobservation site 8C.

Each of the recorders 30 collects the ambient sound for a predeterminedperiod of time (for one day for example), like the first exampleembodiment. Each of the recorders 30 stores the collected sounds in aninternal storage medium as audio data of the time series, for example.

The information emission devices 11 are arranged in such a way that eachrecorder 30 detects the sound emitted by at least one of the informationemission devices 11. In the example of FIG. 3, information emissiondevices 11 are arranged near the recorders 30 (a position the emittedtime information may be recorded) respectively. Hereinafter, forillustrative purpose, each of the information emission devices 11 may begiven a reference sign attached with the same alphabet (A, B, C) as theone attached to the reference sign of the recorder 30 that is arrangedat the same observation site as the information emission device 11. Inaddition, for illustrative purpose, hereinafter, the internalconfiguration of each of the information emission devices 11 may beexpressed with a reference signs attached with the same alphabet as theone attached to the information emission device 11 that includes theconfiguration.

In an embodiment where the time information emitted by the sameinformation emission device 11 can be recorded by some recorders 30, thenumber of the information emission devices 11 may not be the same as thenumber of the recorders 30.

The configuration of the information emission device 11 may be similarto the configuration described in the first example embodiment. In thepresent example embodiment, the clocks 110 of the information emissiondevices 11 are calibrated to one time system (for example, the standardtime of the country).

Information of the timing stored in the timing storage unit 112 of eachof the information emission devices 11 may be the same, or may bedifferent. The timing storage units 112 may store, depending on theobservation site, the time at which the collection of the sound to becollected at the observation site is less likely to be disturbed. As aresult, the possibility that the detection of the audio event at eachobservation site is disturbed by time information can be decreased.

The time codes of time information generated by time informationgeneration units 113A to 113C may be different, or may be the same. Forexample, the time code defined in the time information generation unit113A may be a signal that is translated into audio by an audio modem,and the time code defined in the time information generation unit 113Bmay be Morse code, and the time code defined in the time informationgeneration unit 113C may be a signal expressing the time by the numberof times the audio appears.

In addition, the frequency range of the sound of the time informationmay differ at each information emission device 11.

The time information may be configured in such a way that at least theidentification unit 222 described later can correctly detect andidentify the source of emission.

The processing device 22 includes an acquisition unit 221, anidentification unit 222, an adjustment unit 223, a detection unit 224and an output unit 225. The acquisition unit 221, identification unit222, detection unit 224 and the output unit 225 may include similarfunction as the acquisition unit 211, identification unit 212, detectionunit 214 and the output unit 215 of the first example embodiment,respectively.

The acquisition unit 221 acquires audio data from each of the recorders30.

The identification unit 222 detects the time information from each audiodata. The identification unit 222 decodes the time code and identifiesthe time acquired by decoding as the time at which the time informationis emitted. As a result, the identification unit 222 is able to relate,to each of the audio data, the time provided by the clock 110 of theinformation emission device 11 arranged at the observation site at whichthe audio data are collected.

The adjustment unit 223 relates a single time axis to each audio data.In other words, the adjustment unit 223 adjusts the time axis of eachaudio data into a unified time axis.

For instance, adjustment method of adjusting the time axes of the audiodata respectively acquired by recorder 30A and recorder 30B will bedescribed. For example, the audio data respectively acquired by therecorder 30A and recorder 30B are the time series data illustrated inFIG. 4 (in FIG. 4, the each of audio data is illustrated in a waveform,with the time as the horizontal axis and the amplitude as the verticalaxis). In FIG. 4, the signals Sa1 and Sa2 are the time informationsignals that are identified in the audio data provided by the recorder30A. The signals Sb1 and Sb2 are the time information signals that areidentified in the audio data provided by the recorder 30B.

For the audio data, the adjustment unit 223 firstly relates the timeaxis T to the audio data generated by the recorder 30A. Specifically,the adjustment unit 223 matches the time axis of the audio data and thetime axis T in such a way that the time signified by the signal Sa1 onthe time axis T corresponds to the time at which the signal Sa1 isdetected (assumed to be Ta1), for example.

FIG. 5 is a diagram illustrating a concept of adjusting the time axes.In FIG. 5, a diagram in which the point Ta1 on the time axis T and thetime at which the signal Sa1 is detected are aligned in the verticaldirection of the paper is illustrated. Then, the adjustment unit 223similarly relates the time signified by the signal Sb1 on the referencetime axis T (assumed to be Tb1) to the point at which the signal Sb1 isdetected. When the Ta1 and Tb1 are equal, the signal Sa1 and the signalSb1 are at the same position on the time axis T, as illustrated in FIG.5. The adjustment unit 223 may adjust the time axis of the audio data onthe basis of the signal Sa2 or signal Sb2.

When time units (in other words, length per frame) of the two audio dataare different, the adjustment unit 223 may expand/contract the time axisof one audio data on the basis of the signals Sa1, Sa2, Sb1 and Sb2. Theadjustment unit 223 may adjust the time axis on the basis of therecording speed defined in the recorders 30. The recording speed isexpressed as sample per second or the like when the recording method ofthe recorders 30 is digital, or as millimeter per second or the likewhen the recording method of the recorders 30 is analog recording by ananalog tape recorder.

Similarly, the adjustment unit 223 relates the time axis of the audiodata by the recorder 30C to the reference time axis.

With the above processing, the time axes of the plurality of audio dataare unified. In other words, the processing device 22 is able to dealwith each audio data in a unified time axis.

The detection unit 224 detects an specified audio event. The detectionunit 224 detects the audio event that is detected at the same time onthe plurality of audio data. The detection unit 224 may detects an audioevent from the entirety of the audio data or a part of the audio data.For example, a user may specify the range of the time in which thedetection unit 224 detects an audio event.

Specifically, in the plurality of audio data, the detection unit 224extracts audio events whose types are the same and whose time is thesame on the unified time axis as the audio events that originate fromthe same event.

As an example, the specified audio events are assumed to be three typesthat are a scream, a glass breaking sound and a sound of hitting a claywall.

For example, when a scream is detected at a certain time in the audiodata by the recorder 30A, and a scream is also detected at the same timein the audio data by the recorder 30B, the two audio events are theaudio events that originate from the same scream.

For example, when a scream is detected at a certain time in the audiodata by the recorder 30A, and the audio event detected at the same timein the audio data by the recorder 30B is the glass breaking sound, thetwo audio events are not the same.

Note that “same time” does not mean an exact match. However, it meansthat the times are close enough to each other so that times can beregarded as the same. When defining the degree of proximity that isregarded as “same”, the accuracy of the internal time, the difference ofprocessing speed of each information emission device 11, and thedifference of time the sounds reach the recorders 30 may be taken intoconsideration. For example, the detection unit 224 may regard aplurality of audio events whose time difference is less than one secondas the audio events that originate from the same event.

The detection unit 224 passes the type and time of the audio events thatare regarded as originating from the same event to the output unit 225.

The output unit 225 outputs information related to the audio events thatare regarded as originating from the same event. For example, the outputunit 225 may display, with respect to the audio events that are regardedas originating from the same event, the type, observation sites wherethe event is recorded, and the time when the event is recorded on ascreen. The output unit 225 may inform using a sound or the like that anaudio event is widely detected. The output unit 225 may display theobservation sites at which the recorders 30 that recorded the audioevent are arranged on a map. The output unit 225 may control asurveillance camera that is arranged in such a way as to be able toobserve an observation site where the recorders 30 that recorded theaudio event were arranged to capture the area including the observationsite.

<Operation>

A flow of an operation of the processing device 22 according to thesecond example embodiment will be described with reference to the flowchart of FIG. 6.

Firstly, the acquisition unit 221 acquires the audio data acquired bythe recorders 30A to 30C (step S71). Next, the identification unit 222identifies the time information included in each audio data (step S72).

Then, the adjustment unit 223 adjusts the time axis of each audio dataon the basis of the identified time information (step S73).

Meanwhile, the detection unit 224 detects an audio event from each audiodata (step S74). Then, the detection unit 224 determines whether thereare audio events that are detected at the same time on a plurality ofaudio data (step S75). When applicable audio events exist (YES in stepS75), determination of whether the types of the audio events thatoccurred at the same time are the same is performed (step S76). When thetypes of the audio events are the same (YES in step S76), theinformation related to the audio events is output (step S77). When theresult of the determination at step S75 or step S76 is NO, the operationof the processing device 22 terminates.

The process of the step S74 may be performed before the process of stepS72 and the process of step S73. Moreover, the detection unit 224 maydetermine, after extracting audio events having the same type, whetherthe time at which the audio events occurred is the same.

<Effect>

With the signal processing system according to the second exampleembodiment, the same event that is recorded on two or more recorders 30can be detected. The reason is that the adjustment unit 223 relates thesingle time axis to the audio data on the basis of the time informationincluded in each audio data, and the detection unit 224 detects audioevents of the same type that are recorded by a plurality of recorders 30at the same time on the time axis.

In other words, the processing device 22 can synchronize a plurality ofaudio data using the identification unit 222 and the adjustment unit223.

(Modification)

The clock 110 does not need to be calibrated to a single time system solong as the processing device 22 is configured to be able to acquire thetime provided by the clocks 110 of the information emission devices 11.The information emission devices 11 only need to have internal time.

For example, even when the clocks 110A and 110B are not calibrated to asingle time system, if how much the time provided by the clock 110A isdifferent from the time provided by the clock 110B is known, theadjustment unit 223 can unify the time axes of the two audio data. Theadjustment unit 223 may adopt the time axis of the clock 110A as thesingle time axis T, for example. When the delay of the clock 110B fromthe clock 110A is td, the adjustment unit 223 may, as illustrated inFIG. 7, shift the time axis of the audio data of the recorder 30B by tdfrom the time axis in the case of assuming that the clock 110B ismatching the clock 110A. The value of td can be calculated by theadjustment unit 223 acquiring the time provided by the clock 110A andthe time provided by the clock 110B respectively at any timings, forexample.

When the accuracy of time function of each clock 110 is low or unknown,the adjustment unit 223 may acquire the time provided by each clock 110a plurality of times. The adjustment unit 223 may correct the timesignified by the time information to a plausible time through analyzing,on the basis of the time acquired the plurality of times,characteristics and tendency of the shifting of the time provided by theclocks 110 from the standard time system. As a result, the adjustmentunit 223 can adjust the time axis of each audio data with higheraccuracy.

In the above-described modification, the similar effect as the secondexample embodiment can be obtained.

Third Example Embodiment

A signal processing system 3 according to a third example embodiment ofthe present invention will be described. The signal processing system 3is a modification of the signal processing system 2 according to thesecond example embodiment. The component of the third example embodimentto which a name and a reference sign that are the same as those of thesecond example embodiment is given has a similar function unlessotherwise noted.

In the present example embodiment, it is assumed that pieces of timeinformation that are emitted from different information emission devices11 are recorded on at least one recorder 30. In this case, the clocks110 of the different information emission devices 11 may not becalibrated to a single time system.

FIG. 8 is a block diagram illustrating a configuration of the signalprocessing system 3 according to the third example embodiment of thepresent invention. As illustrated in FIG. 8, it is assumed that the timeinformation emitted by the information emission device 11B is alsorecorded by the recorder 30A.

In this case, audio data generated by the recorder 30A will be asillustrated in FIG. 9. In other words, the identification unit 222detects time information signals Sa3 and Sa5 emitted by the informationemission device 11A and time information signals Sa4 and Sa6 emitted bythe information emission device 11B from the audio data of the recorder30A.

When two pieces of time information are configured in such a way thatthe two pieces of time information can be distinguished from one another(for example, the frequency range is different, or the signified time isdifferent or the like), the identification unit 222 can identify, oneach audio data, which of the information emission devices 11 emittedeach of time information. The identification unit 222 may identify thesource of emission of the time information on the basis of the positionand the direction of the recorder 30A and the volume of the detectedtime information.

Then, the identification unit 222 identifies the difference among eachclock 110 of each information emission device 11, on the basis of theidentified signal.

For example, it is assumed that the signal Sa3 is the signal of a soundemitted from the information emission device 11A at seven o'clock (basedon the clock 110A), and the signal Sa4 is the signal of a sound emittedfrom the information emission device 11B at seven o'clock (based on theclock 110B). In such a case, the delay of the signal Sa4 relative to thesignal Sa3 is the delay of the clock 110B relative to the clock 110A, inother words, the difference between the clock 110A and the clock 110B.

Note that, in the above description and the below description, it isassumed that the difference of the arrival time of the sounds due to thedifference of distance between the recorder 30A and each informationemission device 11 is negligibly small. In practice, when the differenceof the arrival time is not negligible, the difference may beappropriately compensated by the identification unit 222 or the like.

The timing at which the signal is emitted may be different depending oneach information emission device 11. In the above example, the signalSa3 is the signal of a sound emitted from the information emissiondevice 11A at seven o'clock (based on the clock 110A), and the signalSa4 is the signal of a sound emitted from the information emissiondevice 11B at eight o'clock (based on the clock 110B). In the aboveconfiguration, when the difference of the emission time between thesignal Sa4 and the Sa3 is 61 minutes, the clock 110B is understood to beone minute behind relative to the clock 110A.

The adjustment unit 223 may unify the time axis of the audio datagenerated by the recorder 30A and the time axis of the audio datagenerated by the recorder 30C on the basis of the identified difference.For example, when the clock 110B is one minute behind relative to theclock 110A, after relating the two audio data to the single time axis,the time axis of the audio data generated by the recorder 30B may bemoved forward by one minute relative to the single time axis.

With the signal processing system according to the third exampleembodiment, the audio data of the recorders 30A to 30C may besynchronized even when the time of the clocks 110A to 110C is notcalibrated to the single time system and the time provided by each clock110A to 110C is diverse. Therefore, the detection unit 224 can detectthe same audio event that is recorded on two or more recorders, like thesecond example embodiment.

(Another Example of Identifying Source of Emission)

The information emission device 11 that is the source of emission of thetime information can be identified by configuring the recorder 30A torecord the time information from at least one information emissiondevice 11 at least twice. For example, it is assumed that three signalsthat do not directly show the time are detected in the audio data. Thedetected times of the three signals are t1, t2, t3 in the order ofdetection, the signal recorded the earliest on the time series havingthe highest priority. It is assumed that times A1 and A2 are stored intiming storage unit 112A, and a time B1 is stored in timing storage unit112B. The identification unit 222 identifies the source of emission ofeach signal by comparing t1 to t3 with A1, A2 and B1. For example, whenthe difference between A1 and A2 is equal to the difference between t1and t3, the signals of the sounds emitted at times t1 and t3 can beidentified as the signals of the sounds emitted by the informationemission device 11A. Moreover, the signal of the sound emitted at t2that is unidentified can be identified as the signal of the soundemitted by the information emission device 11B. With the information ofA1, A2 and B1, the identification unit 222 can identify the differencebetween the clocks 110 of the two information emission devices 11. Notethat, when the difference between A1 and A2 is equal to the differencebetween t1 and t2, and equal to the difference between t2 and t3, thesource of emission would not be identified. In order to avoid the aboveissue, larger number of pieces of time information may be emitted by theinformation emission device(s) 11.

Fourth Example Embodiment

A signal processing system 4 according to a fourth example embodiment ofthe present invention will be described. The signal processing system 4is a modification of the signal processing system 2 according to thesecond example embodiment. The component of the fourth exampleembodiment to which a name and a reference sign that are the same asthose of the second example embodiment is given has a similar functionunless otherwise noted.

FIG. 10 is a block diagram illustrating a configuration of the signalprocessing system 4 according to the fourth example embodiment of thepresent invention. In the present example embodiment, it is assumed thatthe time information emitted by the information emission device 11A isrecorded by the recorder 30A and recorder 30B, and the time informationemitted by the information emission device 11B is recorded by therecorder 30B and recorder 30C. In FIG. 10, the areas each of which thesound emitted by the information emission device 11 is detected by therecorder 30 in are illustrated by broken lines.

In such a case, the identification unit 222 is able to relate the timeprovided by the clock 110A of the information emission device 11A to theaudio data of the recorder 30A and the recorder 30B. In addition, theidentification unit 222 is able to relate the time provided by the clock110B of the information emission device 11B to the audio data of therecorder 30B and the audio data by the recorder 30C.

Since the audio data of the recorder 30B includes not only the timeinformation emitted by the information emission device 11A but also thetime information emitted by the information emission device 11B, theidentification unit 222 is able to identify the time difference betweenthe clock 110A and the clock 110B.

With the above configuration, the adjustment unit 223 is able to relatethe audio data of the recorder 30C to which the time on the basis of theclock 110B is related to the time on the basis of the clock 110A of theinformation emission device 11A.

Therefore, with the configuration, even when each of the informationemission devices 11 is not calibrated to standard time, and the timeinformation by a plurality of information emission devices 11 is notrecorded on the recorders 30A and 30C, the adjustment unit 223 is ableto relate the same time axis to each audio data of the recorders 30A andthe 30C.

Fifth Example Embodiment

As a fifth example embodiment of the present invention, a processingdevice 20 including a major configuration of the present invention isdescribed.

FIG. 11 is a block diagram illustrating a configuration of theprocessing device 20 according to the fifth example embodiment. Theprocessing device 20 includes an acquisition unit 201 and anidentification unit 202.

An operation of the processing device 20 will be described withreference to the flow chart of FIG. 12.

Firstly, the acquisition unit 201 acquires the audio data in which audiois recorded (step S121).

Then, the identification unit 202 detects a signal that is included inthe audio data and that enables identification of time at which thesignal is recorded (step S122). The time mentioned above is the time insome time system. For example, the time mentioned above is the internaltime of the device that emitted the signal. When the internal time ofthe device is calibrated to standard time, the time at which the signalis generated can be related to the standard time. When the differencebetween the internal time of the device and the internal time of anotherdevice is known, the time at which the signal is generated can also berelated to the internal time of the other device.

Then, the identification unit 202 identifies, on the basis of thedetected signal, the time at which another signal included in the audiodata is recorded (step S123).

FIG. 13 is a block diagram illustrating a configuration of a signalprocessing system 5 including the processing device 20. The signalprocessing system 5 includes the information emission device 10 inaddition to the processing device 20.

The information emission device 10 emits a signal which enablesidentification of the time at which the signal is generated under astandard time, in such a way that the signal is recorded by a recorder(not illustrated in the diagram) that continually records, for example,an environmental sound. With such a configuration, the recordergenerates audio data including the signal that the information emissiondevice emitted.

On the basis of the audio data generated by the recorder 30, theprocessing device 20 can acquire information about the time at which theaudio data is generated. The reason is that, the signal included in theaudio data shows the time at which the signal is emitted.

(About Hardware)

In the example embodiments of the present invention described above,each of components of the devices indicates a block on a function basis.A part or the entirety of the components of devices is achieved by apossible combination of, for example, a computer 1400 as illustrated inFIG. 14 and a program. The computer 1400 includes, as one example,configurations as follows.

a CPU (Central Processing Unit) 1401

a ROM (Read Only Memory) 1402

a RAM (Random Access Memory) 1403

a program 1404A and stored information 1404B to be loaded on RAM 1403

a storage device 1405 to store the program 1404A and stored information1404B

a drive device 1407 that reads from/writes on a recording medium 1406

a communication interface 1408 connected with the communication network1409

an input/output interface 1410 that inputs/outputs data

a bus 1411 that connects the components

Each of the components of the devices in the example embodiments areachieved when the CPU 1401 runs the program 1404A achieving functionsthereof after loading the program 1404A onto the RAM 1403. The program1404A that achieves the function of the components of the devices is,for example, preliminarily stored on the storage device 1405 or ROM1402, and the CPU 1401 reads the program when necessary. The program1404A may be supplied to the CPU 1401 via the communication network1409, or may be preliminarily stored on the storage medium 1406, and thedrive device 1407 may read the program and provide the program to theCPU 1401.

The method for achieving each device has various modifications. Each ofthe components of the devices may be achieved by a possible combinationof a separate computer 1400 and a program, for example. In addition, aplurality of components included in the devices may be achieved by apossible combination of one computer 1400 and a program.

A part or the entirety of the components of the devices is achieved byanother general or dedicated circuit, a computer, or a combinationthereof. These may be formed by a single chip, or may be formed by aplurality of chips that are connected via a bus.

When a part or the entirety of the components of the devices is achievedby a plurality of computers, circuits or the like, the plurality ofcomputers, circuits or the like may be arranged in a concentrated manneror may be arranged in a distributed manner. For example, the computers,circuits or the like may be achieved in such a way that each of them isconnected by a communication network, such as a client and serversystem, a cloud computing system or the like.

The present invention is not limited to the above-described exampleembodiments. Within the scope of the present invention, the presentinvention may be applied with various changes that may be understood bya person skilled in the art.

The present application claims the benefits of priority based onJapanese Patent Application No. 2016-123771, filed on Jun. 22, 2016, theentire disclosure of which is incorporated herein by reference.

All or part of the example embodiments described above may be describedas in the following supplementary notes, but the present invention isnot limited thereto.

(Supplementary Note 1)

A processing device comprising:

acquisition means for acquiring recorded audio data; and identificationmeans for: detecting a signal of a sound included in the audio data, thesignal being emitted from an information emission device and enablingidentification of time at which the signal is recorded; and identifying,based on the signal, time at which another signal included in the audiodata is recorded.

(Supplementary Note 2)

The processing device according to Supplementary Note 1, furthercomprising:

detection means for detecting an audio event which is a predeterminedtype of sound as the another signal; and

output means for outputting information based on a result of identifyingtime at which the audio event is recorded by the identification means.

(Supplementary Note 3)

The processing device according to Supplementary Note 2, wherein

the acquisition means acquires first audio data including the signal andsecond audio data including the signal, and

the detection means detects the audio event that occurred at a same timein the first audio data and in the second audio data.

(Supplementary Note 4)

The processing device according to Supplementary Note 2 or 3, whereinthe information emission device emits the signal at time that is setdifferently from predetermined time at which the audio event is likelyto occur.

(Supplementary Note 5)

The processing device according to any one of Supplementary Notes 2 to4, wherein a frequency of the signal is a frequency in a frequency banddifferent from a predetermined frequency band of the audio event.

(Supplementary Note 6)

The processing device according to any one of Supplementary Notes 1 to5, further comprising:

adjusting means for acquiring a difference between internal time ofdifferent information emission devices, and for relating, based on thedifference, a single time axis to two or more audio data,

wherein the acquisition means acquires the two or more audio dataincluding the signals from the different information emission devices.

(Supplementary Note 7)

The processing device according to Supplementary Note 6, wherein theadjusting means identifies a difference of internal time of two or moreinformation emission devices based on audio data including signals fromthe two or more information emission devices, and relates, based on thedifference, each of different audio data including the signal from oneof the information emission devices to a single time axis.

(Supplementary Note 8)

A signal processing system comprising:

the processing device according to any one of Supplementary Notes 1 to7; and

the information emission device that emits the signal in such a way thatthe signal is recorded by a recorder for recording the audio data.

(Supplementary Note 9)

A processing method comprising:

acquiring recorded audio data;

detecting a signal of a sound included in the audio data, the signalbeing emitted from an information emission device and enablingidentification of time at which the signal is recorded; and

identifying, based on the signal, time at which another signal includedin the audio data is recorded.

(Supplementary Note 10)

The processing method according to Supplementary Note 9, comprising:

detecting an audio event which is a predetermined type of sound as theanother signal; and

outputting information based on a result of identifying time at whichthe audio event is recorded.

(Supplementary Note 11)

The processing method according to Supplementary Note 10, comprising:

acquiring first audio data including the signal and second audio dataincluding the signal; and

detecting the audio event that occurred at a same time in the firstaudio data and in the second audio data.

(Supplementary Note 12)

The processing method according to Supplementary Note 10 or 11, whereinthe information emission device emits the signal at time that is setdifferently from predetermined time at which the audio event is likelyto occur.

(Supplementary Note 13)

The processing method according to any one of Supplementary Notes 10 to12, wherein a frequency of the signal is a frequency in a frequency banddifferent from a predetermined frequency band of the audio event.

(Supplementary Note 14)

The processing method according to any one of Supplementary Notes 9 to13, comprising:

acquiring two or more audio data including signals from differentinformation emission devices;

acquiring a difference between internal time of the differentinformation emission devices; and

relating, based on the difference, a single time axis to the two or moreaudio data.

(Supplementary Note 15)

The processing method according to Supplementary Note 14, comprisingidentifying a difference of internal time of two or more informationemission devices based on audio data including signals from the two ormore information emission devices, and relates, based on the difference,each of different audio data including the signal from one of theinformation emission devices to a single time axis.

(Supplementary Note 16)

A computer-readable storage medium storing a program that causes acomputer to perform:

acquisition processing for acquiring recorded audio data; and

identification processing for: detecting a signal of a sound included inthe audio data, the signal being emitted from an information emissiondevice and enabling identification of time at which the signal isrecorded; and identifying, based on the signal, time at which anothersignal included in the audio data is recorded.

(Supplementary Note 17)

The storage medium according to Supplementary Note 16, wherein theprogram further causes the computer to perform:

detection processing for detecting an audio event which is apredetermined type of sound as the another signal; and

output processing for outputting information based on a result ofidentifying time at which the audio event is recorded by theidentification processing.

(Supplementary Note 18)

The storage medium according to Supplementary Note 17, comprising:

the acquisition processing comprises acquiring first audio dataincluding the signal and second audio data including the signal; and

the detection processing comprises detecting the audio event thatoccurred at a same time in the first audio data and in the second audiodata.

(Supplementary Note 19)

The storage medium according to Supplementary Note 17 or 18, wherein theinformation emission device emits the signal at time that is setdifferently from predetermined time at which the audio event is likelyto occur.

(Supplementary Note 20)

The storage medium according to any one of Supplementary Notes 17 to 19,wherein a frequency of the signal is a frequency in a frequency banddifferent from a predetermined frequency band of the audio event.

(Supplementary Note 21)

The storage medium according to any one of Supplementary Notes 16 to 20,wherein

the acquisition processing comprises acquiring two or more audio dataincluding signals from different information emission devices, and

the program further causes the computer to perform adjustment processingfor acquiring a difference between internal time of the differentinformation emission devices and relating, based on the difference, asingle time axis to the two or more audio data.

(Supplementary Note 22)

The storage medium according to Supplementary Note 21, wherein theadjustment processing comprises identifying a difference of internaltime of two or more information emission devices based on audio dataincluding signals from the two or more information emission devices, andrelating, based on the difference, each of different audio dataincluding the signal from one of the information emission devices to asingle time axis.

REFERENCE SIGNS LIST

-   -   1˜5 signal processing system    -   8A, 8B, 8C observation site    -   10,11 information emission device    -   20˜24 processing device    -   30 recorder    -   110 clock    -   111 control unit    -   112 timing storage unit    -   113 time information generation unit    -   114 time code storage unit    -   115 emission unit    -   201,211,221 acquisition unit    -   202,212,222 identification unit    -   223 adjustment unit    -   214,224 detection unit    -   215,225 output unit    -   1400 computer    -   1401 CPU    -   1402 ROM    -   1403 RAM    -   1404A program    -   1404B stored information    -   1405 storage device    -   1406 recording medium    -   1407 drive device    -   1408 communication interface    -   1409 communication network    -   1410 input/output interface    -   1411 bus

What is claimed is:
 1. A processing device comprising: a memory; and aprocessor coupled to the memory and configured to: acquire recordedaudio data; detect a signal of a sound included in the audio data, thesignal being emitted from an information emission device and enablingidentification of time at which the signal is recorded; and identify,based on the signal, time at which another signal included in the audiodata is recorded.
 2. The processing device according to claim 1, whereinthe processor is further configured to: detect an audio event which is apredetermined type of sound as the another signal; and outputinformation based on a result of identifying time at which the audioevent is recorded.
 3. The processing device according to claim 2,wherein the processor is configured to: acquire first audio dataincluding the signal and second audio data including the signal, anddetect the audio event that occurred at a same time in the first audiodata and in the second audio data.
 4. The processing device according toclaim 2, wherein the information emission device emits the signal attime that is set differently from predetermined time at which the audioevent is likely to occur.
 5. The processing device according to claim 2,wherein a frequency of the signal is a frequency in a frequency banddifferent from a predetermined frequency band of the audio event.
 6. Theprocessing device according to claim 1, wherein the processor is furtherconfigured to: acquire two or more audio data each of which includes thesignal from at least one of a plurality of information emission devices,each of the plurality of information emission devices functioning as theinformation emission device; acquire a difference between internal timeof information emission devices that emitted signals recorded in the twoor more audio data; and relate, based on the difference, a single timeaxis to the two or more audio data.
 7. The processing device accordingto claim 6, wherein the processor is configured to: acquire at least oneaudio data recording two or more signals emitted by differentinformation emission devices among the plurality of information emissiondevices; identify a difference of internal time of the differentinformation emission devices based on the at least one audio data; andrelate, based on the difference, the single time axis to the two or moreaudio data recording the signal from one of the different informationemission devices.
 8. (canceled)
 9. A processing method comprising:acquiring recorded audio data; detecting a signal of a sound included inthe audio data, the signal being emitted from an information emissiondevice and enabling identification of time at which the signal isrecorded; and identifying, based on the signal, time at which anothersignal included in the audio data is recorded.
 10. The processing methodaccording to claim 9, comprising: detecting an audio event which is apredetermined type of sound as the another signal; and outputtinginformation based on a result of identifying time at which the audioevent is recorded.
 11. The processing method according to claim 10,comprising: acquiring first audio data including the signal and secondaudio data including the signal; and detecting the audio event thatoccurred at a same time in the first audio data and in the second audiodata.
 12. The processing method according to claim 10, wherein theinformation emission device emits the signal at time that is setdifferently from predetermined time at which the audio event is likelyto occur.
 13. The processing method according to claim 10, wherein afrequency of the signal is a frequency in a frequency band differentfrom a predetermined frequency band of the audio event.
 14. Theprocessing method according to claim 9, comprising: acquiring two ormore audio data each of which includes the signal from at least one of aplurality of information emission devices, each of the plurality ofinformation emission devices functioning as the information emissiondevice; acquiring a difference between internal time of informationemission devices that emitted signals recorded in the two or more audiodata; and relating, based on the difference, a single time axis to thetwo or more audio data.
 15. (canceled)
 16. A non-transitorycomputer-readable storage medium storing a program that causes acomputer to perform: acquisition processing for acquiring recorded audiodata; and identification processing for: detecting a signal of a soundincluded in the audio data, the signal being emitted from an informationemission device and enabling identification of time at which the signalis recorded; and identifying, based on the signal, time at which anothersignal included in the audio data is recorded.
 17. The storage mediumaccording to claim 16, wherein the program further causes the computerto perform: detection processing for detecting an audio event which is apredetermined type of sound as the another signal; and output processingfor outputting information based on a result of identifying time atwhich the audio event is recorded by the identification processing. 18.The storage medium according to claim 17, comprising: the acquisitionprocessing comprises acquiring first audio data including the signal andsecond audio data including the signal; and the detection processingcomprises detecting the audio event that occurred at a same time in thefirst audio data and in the second audio data.
 19. The storage mediumaccording to claim 17, wherein the information emission device emits thesignal at time that is set differently from predetermined time at whichthe audio event is likely to occur.
 20. The storage medium according toclaim 17, wherein a frequency of the signal is a frequency in afrequency band different from a predetermined frequency band of theaudio event.
 21. The storage medium according to claim 16, wherein theacquisition processing comprises acquiring two or more audio data eachof which includes the signal from at least one of a plurality ofinformation emission devices, each of the plurality of informationemission devices functioning as the information emission device, and theprogram further causes the computer to perform adjustment processing foracquiring a difference between internal time of information emissiondevices that emitted signals recorded in the two or more audio data, andrelating, based on the difference, a single time axis to the two or moreaudio data.
 22. The storage medium according to claim 21, wherein theacquisition processing comprises acquiring at least one audio datarecording two or more signals emitted by different information emissiondevices among the plurality of information emission devices, and theadjustment processing comprises: identifying a difference of internaltime of the different information emission devices based on the at leastone audio data; and relating, based on the difference, the single timeaxis to the two or more audio data recording the signal from one of thedifferent information emission devices.